1. Introduction
The gap is the horizontal space between the edge of the platform and the edge of the rail car door and the vertical difference from the top of the platform and the top of the rail car door. A horizontal gap of some size between a train and the train station platform is necessary to allow the safe passage of trains through stations. If the horizontal gap is too narrow, the dangerous potential exists that the train could strike the platform thereby causing train derailment, injury to commuters and damage to both the train and the platform. The complexities of any potential solution to gap minimization, while setting and maintaining an acceptable gap, is an extremely complicated process affected by the confluence of factors pertaining to variations in car body widths and lengths for typical freight and passenger rail vehicles, track curvature and platform configuration. The problems and solution analysis associated with the passenger boarding process are exacerbated due to the necessary use by freight trains or other specialized equipment of the same track utilized by commuter trains.
Presently, the only federal law mandating that there be any standard for the width of the gap between the train car and platform edge for purposes of passenger safety in boarding and alighting a train is the Americans with Disabilities Act (ADA) with the implementing regulations of the U.S. Department of Transportation (DOT).
The ADA became law on Jul. 26, 1990. All transit line systems, subject to the law's applicability, must take into account the ADA when giving consideration to new station construction, station modernization, retrofitting of existing fleet and purchase of new train cars. This federal law, with its accompanying DOT regulations initially adopted in 1991, became the first statutory mandate prescribing a maximum gap width standard for the protection of commuters with disabilities while boarding and alighting trains.
The existing regulations of the DOT, in part, incorporating the ADA Accessibility Guidelines (ADAAG) created by the Architectural and Transportation Barriers Compliance Board (Access Board), implementing the mandates of the ADA generally specify that there be a horizontal gap of no more than 3″ between train car doorway and the platform in rapid rail, light rail, commuter rail, intercity rail and high speed rail systems.
The regulatory language as to light rail, commuter rail and intercity rail systems presently provides, in part, that where meeting the horizontal gap requirement is not operationally or structurally feasible the use of mini-high platforms, car-borne or platform-mounted lifts, ramps, bridge plates or similarly manually deployed devices meeting DOT specifications is then permitted.
According to current DOT regulations, a recipient of DOT funds under any program or activity cannot exclude from participation in such program or activity any qualified individual with a defined disability and must provide such service in the most integrated setting that is reasonably achievable. In rail transportation, the accessibility solution which accomplishes the providing of such services to the disabled in the most integrated setting must be selected by the carrier.
The norm for new commuter and intercity rail stations, according to DOT regulations, is a platform running the full length of the passenger boarding area of the station that permits level boarding to all accessible cars of trains stopping at the station thereby avoiding segregated service by permitting passengers with disabilities to have access to all train car doorways of all cars. In 2005, the DOT reported that meeting and/or maintaining the 3″ horizontal gap is likely to be unfeasible for transit line system operators in most commuter and intercity rail stations.
In 2006, the DOT proposed to thus modify its existing 3″ horizontal gap rule at applicable intercity and commuter rail stations such that, where it is not feasible to meet it, the platform design shall be coordinated with rail cars so as to provide full train length level entry boarding with the horizontal gap to be no greater than 10″ on tangent track and 13″ on curves with bridge plates and other devices to be used as permitted by the DOT. No final rule has yet been made.
The Federal Railroad Administration (FRA), an agency of the DOT, also concluded in 2006 that the 3″ horizontal gap requirement specified by the ADA regulations is probably impossible for intercity and commuter rail systems to meet even at stations where only passenger trains are operated.
In response to the need to manage the gap from all perspectives, the federal government, state governments, rail industry associations and transit line systems are currently in the process of developing standards to manage gap safety.
Present state laws and rail industry standards, which relate to the gap distance between the train and the platform, have as their focus the prevention of a train crashing into a fixed station platform during normal operations and were not developed from the perspective of the gap to be crossed by the commuter when boarding or alighting the train. Such gaps are necessary to take into account the normal variability or tolerance in the position of a rail car with the platform in a dynamic system. Tolerance applies to every aspect of any rail system such as, but not limited to, its platform configuration, track structure and fleet; further, it contains both horizontal and vertical components. The distance between the train car and the platform is affected by horizontal components. The height of the car floor in relationship to the platform is affected by vertical components. The tolerance of each factor which affects horizontal or vertical components cumulatively determines each component's respective total variability or tolerance stack. All efforts to manage and minimize both the horizontal and vertical gap must take into account the practicability of minimizing the individual tolerance factors.
The horizontal components affecting gap width are generally acknowledged to be the location of the platform relative to center line of track, variation in track gauge, width of the rolling stock, rail car position relative to center line of track, variation within the rail car suspension, curvature of track and car body roll.
Utilizing mechanical engineering concepts, the tolerance of each factor affecting the horizontal components must be analyzed to determine total variability. According to statistical analysis, this calculation of the tolerance stack determines the required minimum horizontal, that is, side clearance distance to be maintained in order to avoid a worst case scenario of a platform strike. Such will occur if every horizontal component affecting gap width were to be at extreme limits of working tolerances and all were simultaneously acting in the same direction. It is crucial that the side clearance gap be of sufficient width such that the probability of a train colliding with the platform edge approaches zero.
Any horizontal gap minimization attempt from the commuter perspective must be counter-balanced by the impact, if any, which each respective mitigation measure has on the horizontal components which comprise the tolerance stack so as not to exacerbate the probability of a train to platform strike. The interplay between and among the horizontal components affecting gap width and the overall tolerance stack must be understood and analyzed when any attempt is made to mitigate the gap the commuter must cross when boarding or alighting the train by a minimization measure which deals with one or more horizontal components.
Considerations to have the horizontal gap distance be as narrow as possible for the commuter to cross while attempting to achieve and/or maintain compliance with the gap width mandates of the ADA and DOT regulations must be critically juxtaposed against the necessary side clearance distance to be maintained between platform and train required to prevent a catastrophic platform strike by the train.
Simply stated, government and the rail industry today are faced with perplexing gap dilemmas which appear to be irreconcilable. The federal government presently mandates a 3″ maximum gap width derived from the commuter perspective only while its DOT has been forced to acknowledge this requirement is presently impossible to meet by intercity and commuter rail systems. State governments have legislated, and the rail industry has adopted, a necessarily larger gap width standard developed solely from a train clearance perspective.
All transit line systems thus face a seemingly unavoidable and unsolvable predicament, the radically divergent components of which are, to have the gap width the commuter must cross be as narrow as possible while simultaneously needing to maintain a side clearance gap width as broad as required to facilitate the safe passage of every type of rail car in its fleet through a station. Superimposed on this quandary are gap width standards developed and maintained from differing perspectives: the existing federal mandate in the ADA providing generally a very narrow 3″ horizontal gap width to protect commuters with disabilities; mirror imaged against this are state laws and rail industry safety recommendations providing larger gap width standards for train clearance purposes.
2. Background of the Related Art
Gap widths in train stations along the plurality of routes of a transit line system are not uniform in size. It is functionally inadequate to analyze the issue and formulate solutions solely from the perspective of considering every train station within a transit line system as having a uniform gap width along its entire platform.
Each train car doorway of every train has its own gap width issues dependent, in pertinent part, upon its positioning in the line of a trainset, the setback of the platform from the track, platform and track configuration, and the location within each station at which that particular train car doorway opens when the train comes to a stop.
Thus, a differing set of gap width issues must be readily addressable for that same train car doorway at each station the train stops at on every route within the system.
The problem and its attendant solution is made further complex due to the fact that any particular train car may be routinely transferred from one route to another route within the transit line system and which action will present differing gap size issues for each train car doorway of that train on its new route.
It is further pertinent to consider that a transit line system does not necessarily operate with only one type of train car but its fleet may include cars having varied characteristics and different dimensions within the context of passenger service as well as a rail freight operation.
Superimposed upon any particular solution to be considered by any one transit line system is the fact that terminals, stations along a route, and large segments of track may be shared in certain situations with other carriers having fleet differing in size and shape.
Therefore, the prevailing thought is that no single gap solution will work for any transit line system.
A multi-faceted flexible remediation program specifically geared to each transit line system's specialized needs and requirements is the only addressable solution to this most complex set of variables.
Related art reveals numerous attempts at mitigating the above mentioned gap problem. There is no device which functionally addresses gap mitigation solutions for the varying sized gaps existing at each train car doorway with its corresponding train station platform edge of every train of a trainset at every station along a train's route. The devices known to exist claiming to respond to the need for gap mitigation are universally burdened by the common deficiency of having a singular non-flexible approach and thereby being unable to address the goal of mitigating every sized gap at every train car doorway with its corresponding station platform.
The use of a bridge plate device which rests on the station platform to span the gap is disclosed in various patents. For example, U.S. Pat. No. 5,357,869 to Barjolle et al., discloses a bridge plate device housed fully within the thickness of the train car vestibule floor. U.S. Pat. No. 5,775,232 to Golemis, et al., discloses a bridge plate device extending from a so-called “cartridge” design mounted under the train car door. U.S. Pat. No. 6,167,816 to Layery, et al., discloses a bridge plate improvement patent to Golemis, supra.
Common to the above three patents is the housing of the plate component below the train car vestibule floor. In order for the device to be operative, the stowed position of the plate must be higher than the corresponding top of the station platform such that the platform edge can be totally cleared by the device horizontally extending from the train. Disadvantageously, device utilization presumes that for the entire length of each train station platform, the platform must be lower than each train car doorway throughout the entire transit line system or the device cannot be used.
A further distinctive disadvantage is the preset operating position of the device limiting its extension to one predetermined length. There is no disclosure of any provision for varying the length of the device extension into the horizontal plane during train operation for it is the sole purpose of the apparatus to bridge the gap by coming to rest upon the platform. The device can be recalibrated to a different length but, most importantly, this cannot take place during the train's on-going route and must be accomplished during non-operating maintenance conditions. There is no disclosed capability for the device to adjust its length of extension into the horizontal plane between the train and the station platform while the train is on its route.
Further, the distance to be traveled by the device in the horizontal plane is preset at the same length for every train car doorway of the train in the trainset sufficient for every platform to be bridged. The preset distance must obviously be greater than the widest gap existent within the entire transit line system.
Given this undeniable fact and that the actual gap widths at every train car doorway vary in size, and in view of the preset singular length into the horizontal plane to be traveled by each such device, it is axiomatic that the bridge plate at each train car doorway of all trains in the trainset does not overlay the adjoining station platform for a common distance. Thus, the bridge plate type device will unnecessarily overlay the station platform at a plurality of different lengths varying train car doorway to doorway thereby creating an unwarranted and jigsaw-like series of tripping hazards along the entire platform adjacent to the train.
In abandoned U.S. patent application Ser. No. 10/254,929 to Morlok filed Sep. 26, 2002, same discloses extension plates, within the context of a purported new entranceway design covering doors, steps, and other components, which in its activated horizontal position rests upon the platform thereby forming a bridge plate. The bridge plate is housed against the exterior of the train car door and is lowered into position so that it rests on the platform. If the plate does not function according to design, an obvious hazard has been created due to the very location of the device against the exterior of the train car doorway thereby preventing door opening and closing procedures with consequent train delays. No disclosure is made of any embodiment permitting the train operator to utilize the extension plates to cover varying sized gaps, without overlapping the station platform, as it is the purpose of the inventor to bridge the platform with the device.
A common disability of all bridge plate type devices, regardless of its stowed position, is created by the very nature of the apparatus having necessarily to rest upon the train station platform. The sides of the device as well as the front extending edge, even if contoured, are in such position where commuters purposely crowd to board the train simultaneously with those who seek to exit the train car. This problem is exacerbated during the commuter morning and evening rush hours. Commuters do not board or alight the train by walking in a straight path from or to the train car vestibule floor and the platform but take any conceivable path at any angle. The probability of a misstep with resultant injury is heightened by the use of a bridge plate type device.
More importantly, such devices do not address the need, without use of an apparatus which lays upon the train station platform with the attendant problems associated therewith, to mitigate different sized gaps at each doorway of each train on a trainset in every station on a train line's route. Upon activation, the device extends into the crowd. Crowds gather in the area near the expected doorway location before the train comes to a stop in the station. As aforementioned, a tripping hazard is caused due to the introduction of an apparatus on a crowded platform.
Further, timing concerns have not been anticipated, or if so, are not taken into consideration in the implementation of the device pertaining to transit line scheduling. Timing sequence of device activation and deactivation must be taken into account when considering gap solutions.
All related art bridge plate devices suffer from the common deficiency of not being able to specifically address different sized gaps that a train at each train car doorway will encounter while that train is on its route and are relegated to use a one size fits all simplistic approach of having to reach and overlay the station platform.
Given this unalterable fact, the length of the device must be greater than the maximum gap width within the transit line system in order to bridge the platform and further can only be used where each train car doorway at each train station for the entire transit line system is higher than the top of the corresponding platform edge.
Thus, for the entire length of the platform at each train station on all routes within a transit line system, the platform must be lower than each train car doorway of each train in the system's fleet, or the bridge plate type device cannot be used. Therefore, such devices do not have practical use and cannot provide any measurable and meaningful gap solution.
U.S. Pat. No. 7,178,467 to LeBellec, et al., discloses a “strip” apparatus gap filler which is attached to an area of the train below the standard threshold plate so as to fixedly extend outward from the side of the train. The distance that the strip outwardly extends is selected by the user. The train, thus, on its entire route travels with this extension apparatus. The length of the extension can be modified during maintenance. No adjustment is provided for during train operation. An obvious disadvantage of this type device is the probability of unwanted collision between the device and various objects, including the station platform, it can potentially come into contact with during the train's route. Thus, the selected fixed length of the extension would have to be severely limited by normal and expected operating conditions of any train.
This device and any others of its kind fail to take cognizance of the absolute necessity for any transit line system to maintain strict adherence to its gap clearance standards to ensure safe passage of all its fleet through every train station on its entire route system without the potential of damage to the train and the platform and without creating potential for injury to commuters.
3. Gap Mitigation Considerations by Mass Transit and Railroad Systems
The entity in charge of the planning, operation and maintenance of a transit line system must take into consideration gap minimization measures by giving due consideration to the following points of critical analysis:    (1) the differing sized gaps existent within each train station on the train line as measured for each train car door when the train is stopped at each train station.    (2) the consideration of time constraints in the activation and deactivation of any such gap minimization device relative to maintenance of the train line schedule critical to movement of passengers in order to avoid transit congestion especially during the morning and evening rush hours.    (3) the differing gap minimization problems on each train line route as well as on the train line system which the operating entity seeks to address voluntarily or must address due to public demand, governmental directive or law.    (4) the retrofitting of the device of the present invention to the train cars then in use on the transit line system by a cost efficient method.    (5) the age and condition of its existing trains within its transit line system and corresponding needs to replace the older, out-of-date, and/or poorly conditioned trains with new trains then to be properly equipped with gap minimization devices.
It is apparent that the issue of passenger safety, which has come to the national forefront of discussion and concern, has been caused by the focus of attention presently being raised due to the increasing number of gap related incidents causing serious injuries to commuters.
Railroad officials have as their goal the reduction of risk of commuter injuries consistent with the reduction of gaps, wherever possible on their respective rail line systems, sufficient to allow for the safe passage of trains.
Thus, presently the complex problem pervades the entire railroad industry, domestically and internationally, as to the safest methodology to ensure commuter safety during the boarding and alighting process at stations, while simultaneously, duly and properly balancing the absolute necessity for maintaining the appropriate gap required for the safe passage of all trains within its system.
As such, what is needed is a device which simultaneously accomplishes the dual goal of permitting all rail line systems to achieve and/or maintain gap width clearance mandates set in law, by industry standards or recommendations and/or by the rail line system itself ensuring the safe passage of all trains through each of its stations within its system while providing gap mitigation as may be required by law or otherwise necessary to facilitate passenger safety in boarding and alighting trains regardless of size of any existing gap along its route resulting from any cause.